Why can't primates talk?

Answer 1

First of all, humans are primates, and we can talk.

If you want to know why the other primates can't talk, it's because speech involves some very complex and subtle, well-coordinated movements of breath and the organs of the mouth, relative position of tongue and lips and teeth, and other factors. The other primates simply do not have mouth structures that make it possible for them to form the sounds of human speech.